RoccoAndJezebel.com’s Brody Bag comes in two sizes: Mini (8.5Hx14Lx8W) and Medium (9.5Hx16Lx10W). Both would work well as in-cabin airplane carriers. They have lots of mesh ventilation panels, including one on top, so you can see down into the carrier when it’s at your feet. The interior is well-padded and easy to clean, and there are several useful exterior pockets.